Answer 1

The first step for building a program:
1st: know wich language to use and know that language, Otherwise learn and review Before you start.
2. Have a good idea for a program.

Then to your question:
More use is made of a language for simpler codes, but for more complex ones you can also use more programming languages.
But for beginners i suggest to start with one language at program.
You can use libraries too.

Hope I helped you 😄.